Binary semiconducting oxides often have distinctive properties and can be used as transparent conducting oxide (TCO) materials and gas sensors. Current studies of semiconducting oxides have been focused on two-dimensional films and zero-dimensional nanoparticles. For example, fluorine-doped tin oxide films are used in architectural glass applications because of their low emissivity for thermal infrared heat. Tin-doped indium oxide (TIO) films can be used for flat panel displays (FPDs) due to their high electrical conductivity and high optical transparency, and zinc oxide can be used as an alternative material for TIO because of its lower cost and easier etchability. Tin oxide nanoparticles can be used as sensor materials for detecting the leakage of several inflammable gases, such as carbon monoxide, owing to their high sensitivity to low gas concentrations.
In contrast, investigations of wire-like semiconducting oxide nanostructures can be difficult due to the lack of availability of nanowire structures. Wire-like nanostructures have attracted extensive interest over the past decade due to their great potential for addressing basic issues about dimensionality and space confined transport phenomena, as well as related applications. In terms of geometrical structures, these nanostructures can be classified into two main groups: hollow nanotubes and solid nanowires, which have a common characteristic of cylindrical symmetric cross-sections. Besides nanotubes, many other wire-like nanomaterials, which include carbides, nitrides, compound semiconductors, elemental semiconductors, and oxide nanowires have been successfully fabricated.
However, the nanostructures discussed above can have a variety of deficiencies. For example, often it is difficult to control the structure and morphology of many nanostructures. Thus, a heretofore unaddressed need exists in the industry to address at least the aforementioned deficiencies and/or inadequacies.